Sheet dispenser and dispenser subassemblies

Abstract: A sheet dispenser or sheet dispenser subassembly including a coherent stack of tape flags or other adhesive-bearing sheets that can be unobtrusively permanently or removably adhered on a page of a book, catalog, brochure, etc., because it has a supple cover layer that is a thin, tear-resistant polymeric film. The dispenser subassembly has a pressure-sensitive adhesive layer on a peripheral portion of the cover layer by which it can be adhered to the page which then serves as a back layer for the dispenser, whereas the dispenser includes a bottom layer on an outer surface of which is a layer of pressure-sensitive adhesive layer by which the dispenser can be adhered to a surface.

Description: Field of the Invention The invention relates to dispensers for sheets from a coherent stack of sheets, each sheet bearing a band of pressure-sensitive adhesive, such as a repositionable pressure-sensitive adhesive, by which it can be self-adhered to a variety of surfaces. The invention is particularly related to such dispensers which have a low profiles so that they can be adhered to an inside page of a magazine, catalog, notebook, or the like without creating an unsightly bulge. Description of the Related Art Minnesota Mining and Manufacturing Company or 3M (the company to which this application is assigned) markets a Post-itTM brand repositionable tape flag that can be self-adhered to an object, e.g., to mark a page of a book to draw attention to that page or to specific information on that page. Typical is the tape flag (10) of Figure 1 of co-assigned U.S. Pat. No. 4,907,825 (Miles et al.) which has an elongate layer (11) of flexible polymeric material having a wide band (16) of repositionable pressure-sensitive adhesive covering one major surface of one end (the second end portion 15) of the polymeric material while being free of adhesive on both major surfaces of the other end (the first end portion 19). The first end portion preferably is brightly colored to attract attention while the second end portion is transparent so that it does not obscure a substrate to which it is applied. A dispenser for a coherent stack of tape flags (10) is shown in Figures 3-7 of the Miles et al. patent. In the stack, the first and second end portions of successive tape flags are reversed so that the adhesive of each tape flag adheres to the brightly colored second end portion of the underlying tape flag, except that the lowermost tape flag is adhered to an adhesive-free bottom sheet (33). The bottom sheet, in combination with the low-friction nature of the bottom wall (37) of the dispenser, permits the stack to shuttle back or forth in an elongated closed chamber (38) while successive uppermost tape flags are pulled through a central transverse slot (42). The dispenser of Figures 3 through 7 of the Miles et al patent can be called a "pop-up" dispenser, because upon pulling successive uppermost tape flags through the central transverse slot, an end portion of the next tape flag pops up through the slot. The Miles et al patent shows in Figure 9 a repositionable tape flag (80) which differs from that of Figure 1 in that its band of repositionable pressure-sensitive adhesive (86) covers one entire surface of the polymeric material (81), and release material covers the opposite face of the polymeric material only at one end (85). When a plurality of these tape flags (80) are stacked with the bands of release material of adjacent tape flags at opposite ends of the stack and successive uppermost tape flags are pulled through a central transverse slot (102), the stack shuttles back and forth in an elongated closed chamber (98) and the next tape flag pops up through the slot. For additional disclosure of coherent stacks of adhesive-bearing sheets, see co-assigned U.S. Patent No. 4,895,746 (Mertens) and U.S. Patent No. 5,086,946 (Blackwell). 3M has advertised repositionable tape flags by distributing samples in similar pop-up dispenser that has a low profile to allow it to be incorporated into a magazine, catalog, or the like without an unsightly bulge. This low-profile dispenser employed a laminate including a paper cover layer having an aggressive pressure-sensitive adhesive layer along an inner surface, a central portion of which cover layer was covered by a smaller piece of paper so that the adhesive layer was exposed only around a peripheral portion of the laminate. After forming a central transverse slot through the laminate, a series of the laminates were disposed along a release liner. The pop-up dispensers were then formed by sequentially removing one of the laminates from the liner, positioning a stack of about ten tape flags along the central portion of the laminate on its side adjacent the exposed adhesive with an end portion of the uppermost tape flag on the stack projecting through the slot, and then adhering the adhesive to an advertising sheet so that the central portion of the laminate and adjacent portion of the advertising sheet formed a chamber for the stack of tape flags with an end of the uppermost flag laying flat against the outer surface of the laminate. Printed on the advertising page above and below an arrow that pointed to the protruding tape flag end portion were the words: "Free Samples" and "Pull Up". This dispenser is below called the "Prior Low-profile Tape Flag Dispenser". In the Prior Low-profile Tape Flag Dispenser the stack of tape flags shuttled back and forth in an elongated closed chamber which was longer than the stack. Other rather low profile dispensers are known in which the chamber is about the same size as the stack and the stack does not need to shuttle. Such a dispenser is disclosed in co-assigned U.S. Patent No. 5,158,205 (Bodziak et al.). In Figures 1-6 of the Bodziak patent, a dispenser made of folded card stock forms a chamber closely containing a stack (12) of paper sheets. Centrally across the top wall (22) of that dispenser is a slot (30) through which paper sheets can be successively pulled from the stack. Each of the sheets has a narrow band of repositionable pressure-sensitive adhesive (14) coated on one surface adjacent one edge. When the uppermost sheet of the stack is pulled through the slot, flanking slits (24) at each end of the slot allow one of two opposed flap-like portions (28) of the top wall to flex as shown in Figure 4 while the other flap-like portion places a drag on the next sheet so that the uppermost sheet will peel away from the next sheet. The pop-up dispenser of the Bodziak patent is being used for coherent stacks of Post-itTM brand self-stick repositionable notes that consist of pieces of paper, each having a narrow band of repositionable pressure-sensitive adhesive coated on one surface adjacent one edge. Among a variety of other pop-up dispensers that have been described in the art for use with coherent stacks of Post-itTM brand self-stick repositionable notes are those disclosed in co-assigned U.S. Patents Nos. 4,416,392 (Smith), 4,653,666 (Mertens), 5,080,255 (Windorski), 5,165,570 (Windorski et al), 5,167,346 (Bodziak et al) and 5,158,205 (Bodziak et al). Figures 1-13 of U.S. Patent No. 5,165,570 illustrate dispensers having a base surface bearing a pair of foam-backed pressure-sensitive adhesive strips covered with a release liner by which the dispenser can be adhesively anchored to a substrate. Summary of the Invention The present invention concerns sheet dispenser subassemblies or sheet dispensers including coherent stacks of tape flags or other adhesive-bearing sheets which, when adhered to a substrate, will have low profiles like the above-discussed low-profile dispensers, permitting them to be used unobtrusively on an inside page of a book, catalog, brochure, or the like. The novel sheet dispenser subassemblies differ from the Prior Low-profile Tape Flag Dispenser described above in that they are in a sub-assembled form with stacks of sheets pre-positioned along a cover layer from which they can more easily be applied to substrates that, after such application, form part of the resultant dispenser, which application can be done either manually or by automated equipment such as label applying equipment. The substrates to which the sheet dispenser sub assemblies can be applied, in addition to advertising pages, can easily include the surface of a personal computer or a page or cover of a book, magazine, or personal organizer, or substrates wherever else there is need for convenient access to adhesive-bearing sheets. The sheet dispenser according to the invention is defined in the enclosed claim 1. Generally, the sheet dispenser according to the present invention comprises: A pop-up sheet dispenser comprising: (a) a stack of sheets disposed one on top of another, each sheet comprising a backing having opposite first and second major side surfaces and opposite first and second ends with ends of the sheets being in alignment in the stack, and a layer of adhesive permanently adhered to the first side surface of said backing, the layers of adhesive of said sheets being releasably adhered along the second surfaces of the adjacent sheets in said stack, at least some of said sheets comprising release means for providing a first adhesion level along first end portions of said sheets adjacent said first ends of said backings between said first side surfaces and the second side surfaces of the adjacent sheets in the stack to which the layers of adhesive are releasably adhered, which first adhesion level provides a sufficiently low or no release force between said first side surfaces and the adjacent sheets to which the adhesive along those first side surfaces are releasable adhered to afford sliding movement between the side surfaces of the adjacent sheets along said first end portions, and attachment means for providing a second adhesion level along second end portions of said sheets adjacent said second ends of said backings between said layers of adhesive and the second side surfaces of the adjacent sheets in the stack to which said layers of adhesive are releasably adhered, which second adhesion level provides a release force that is higher than said sufficiently low release force along said first end portions and firmly adhere the sheets to the adjacent sheets in the stack during sliding movement of the sheets relative to the adjacent sheets along said first end portions while affording peeling away of the sheets from the stack along said second end portions, (b) a cover layer having inner and outer major surfaces, a central portion, a peripheral portion or portions on at least two opposite sides of said central portion, and a through slot extending transversely across said central portion; (c) said stack of sheets being positioned along the inner surface adjacent said central portion with the first end portion of the uppermost sheet in the stack extending through said slot, (d) a bottom layer having inner and outer surfaces, said bottom layer extending over the inner surface of the cover layer and the stack of sheets and being attached to said peripheral portion of the cover layer with the inner surface of the bottom layer adjacent the cover layer to form a chamber around the stack of sheets; (e) said stack of sheets, slot and chamber being adapted to afford dispensing of the sheet having the first end portion extending through the slot when that first end portion is manually pulled through the slot by sequential sliding movement of one of the sheets relative to the adjacent sheet along the first end portion and peeling away of the sheet from the stack along said second end portion, and positioning of the first end portion of an underlying sheet in a position extending through the slot as a result of said dispensing; (f) said dispenser further including a layer of pressure-sensitive adhesive on the outer surface of the bottom layer; and a disposable release liner over the surface of the layer of pressure-sensitive adhesive layer opposite the bottom layer, which release liner can be removed to permit the dispenser to be adhered to a surface; said pop-up sheet dispenser being characterized by the feature that (g) said cover layer is supple and less than 0.2 millimeter (0.008 inch) in thickness; and (h) said bottom layer is thin and supple. Protective means are provided by the disposable release liner removably adhered to the surface of the layer of pressure-sensitive adhesive on the outer surface of the bottom layer. This release liner can be sized for a single bottom layer or can be an elongated strip on which a plurality of identical pop-up dispensers are positioned. In this way, said elongated strip of disposable release liner supporting pop-up dispensers can be helically wound into a roll for convenient storage and shipment. Moreover, in such a roll, the cover layers or the bottom layers of the successive sheet dispensers can be provided by a substantially continuous polymeric film that is perforated between adjacent pop-up dispensers to afford separation of the pop-up dispensers. In the sheet dispenser, the thin bottom layer prevents the stack from being accidentally displaced upon removal of the disposable release liner, but at the added expense of the bottom layer. The bottom layer preferably is as thin as possible so that the dispenser can be as unobtrusive when self-mounted on a flat surface that is flexible such as a page of a book, catalog, brochure, etc. The cover layer can be of strong, supple tear resistant paper or polymeric material, and can be less than 0.2 millimeter (0.008 inch) in thickness. Preferably the cover layer and, the bottom layer is from 0.02 to 0.1 millimeter (0.00075 to 0.004 inch) in thickness. The bottom layer of the sheet dispenser preferably is strong and tear-resistant like the cover layer and so also can be of a strong tear-resistant paper or polymeric material. A polymeric film material that is useful as both the cover layer and the bottom layer is biaxially oriented polypropylene which is especially useful at thicknesses from 0.02 to 0.05 millimeter (0.00075 to 0.002 inch). Among other useful tear-resistant polymeric films are biaxially oriented polyethylene and biaxially oriented poly(ethyleneterephthalate). The polymeric film used for the cover layer and for the bottom layer can be reinforced by filaments or other fibers including paper. The bottom layer does not always need to be tear-resistant. Because the cover layer and, the bottom layer can be quite thin, each of the sheet dispenser subassembly and the sheet dispenser can have a low profile that is only slightly thicker than its stack. The cover layer and the bottom layer (when present) can be supple so that they do not need to be embossed and so that the sheet dispensers can flex somewhat without being damaged when they are adhered on the surface of a flexible sheet or similar structure. The cover layer also should have good dimensional stability to afford a durable, attractive appearance when it is positioned over the stack. The uppermost sheet that initially extends through the slot can be a disposable leader which, when pulled through the slot, leaves the next (now uppermost) sheet extending through the slot. The layer of pressure-sensitive adhesive by which the sheet dispenser can be adhered to a substrate can be of an aggressive adhesive to afford permanent mounting on most surfaces, or can be of repositionable pressure sensitive adhesive to permit the sheet dispenser subassembly or sheet dispenser to be moved from place to place and eventually removed and discarded after its stack has been exhausted. While some conventional pressure-sensitive adhesives are repositionable, an especially useful unconventional class is based on solid, inherently tacky, elastomeric microspheres, such as pressure-sensitive adhesives disclosed in the following co-assigned patents: U.S. No. 3,691,140 (Silver), 3,857,731 (Merrill et al.), 4,166,152 (Baker et al.), and 4,786,696 (Bohnel), and EP No. 439,941 (Bohnel et al.). The latter discloses a high-tack pressure-sensitive adhesive that would enhance the ability of the novel sheet dispenser or sheet dispenser sub assembly to remain securely mounted on a vertical flat surface. Different types of dispensers including stacks of different types of sheets that, for stacks of only a few sheets, can be emulated by sheet dispensers according to the present invention include those described in U.S. Patent No. 4,907,825 (Miles et al, see Figures 3-7); U.S. Patent No. 5,050,909 (Mertens et al, see Figures 11-13); U.S. Patent No. 5,158,205 (Bodziak, see Figures 1-8), and U.S. Patent No. 5,086,946 (Blackwell et al). Brief Description of the Drawing The present invention will be further described with reference to the accompanying drawing wherein like parts are identified with like reference numerals in the several views and wherein: Figure 1 is a plan view of a first embodiment of a sheet dispenser according to the present invention; Figure 2 is a longitudinal cross section of a sheet dispenser according to the present invention with its release liner being peeled off. Description of the Preferred Embodiments Referring now to Figure 1, there is illustrated an embodiment of a sheet dispenser according to the present invention generally designated by the reference numeral 20. The sheet dispenser 20 includes a thin, supple, elongated, tear-resistant cover layer 21 which is a polymeric film having a central transverse slot 22. Positioned adjacent a central portion 15b of the cover layer 21 along its inner surface is a coherent stack 16 of adhesive-bearing sheets (e.g., a stack 16 of the sheets described in U.S. patent No. 4,907,825. An end portion 27 of the uppermost of the sheets in the stack 16 extends through the slot 22 and lays flat against the exposed outer surface of the cover layer 21. On an underside or second surface of each of the adhesive-bearing sheets is a layer or wide band 18 of pressure-sensitive adhesive adjacent a second end of the sheet, with the wide bands of successive sheets at opposite ends of the stack 16. Both first and second surfaces of each of the adhesive-bearing sheets are free from adhesive along a portion 19 adjacent a first end opposite the second end. That portion 19 of each adhesive-bearing sheet can be brightly colored so that the sheet acts as a tape flag by attracting attention with its brightly colored portion 19 while its adhesive-bearing portion is transparent so that it does not obscure a substrate to which the sheet or tape flag is releasably adhered. Figure 2 illustrates a pop-up sheet dispenser according to the present invention, generally designated by the reference numeral 20. The sheet dispenser 20 has a thin, elongated, tear-resistant cover layer 21 of polymeric film having a layer 23 of permanent adhesive along its inner surface by which the layer 21 of film is laminated to a smaller piece of paper 21b that covers its central portion so that the adhesive layer is exposed only around a peripheral portion of the layer 21 of polymeric film. Extending through the cover layer 21, adhesive layer and paper 21b is a central transverse slot 22. The portion of the layer of adhesive 23 exposed around the piece of paper 21b permanently adheres the cover layer 21 to a thin, supple bottom layer 24. When the layer of adhesive 23 is tack-free, it can be adhered to the piece of paper 21b and to the bottom layer 24 by being activated by heat or ultrasonically. Alternatively the layer 21 of film could be attached to the bottom layer 24 by other means such as heat fusion in which case the layer 23 of adhesive and the piece 21b of paper could be eliminated. Positioned within a closed chamber 25 formed between the central portion of the cover layer 21 and bottom layer 24 is a coherent stack 16 of adhesive-bearing sheets or tape flags, an end portion 19 of the uppermost of which sheets extends through the slot 22 and lays flat against the exposed outer surface of the cover layer 21. The sheets or tape flags of the stack 16 are identical to the adhesive-bearing sheets of the stack 16 illustrated and described with reference to Figure 1. Covering the outer face of the bottom layer 24 is a coating 28 of pressure-sensitive adhesive which is temporarily protected by a release liner 29 that is being peeled off to permit the dispenser 20 to be self-mounted on a flat surface (not shown) by the coating 28 of adhesive. The coating 28 of adhesive can be of aggressive or repositionable adhesive. The sheet dispenser 20 includes stacks of adhesive coated sheets or tape flags that each have a wide band or layer of pressure-sensitive adhesive covering at least 50% of the area of one surface of each sheet. Other dispenser subassemblies or dispensers according to the present invention can include stacks of paper or polymeric sheets that either have a narrow band or layer(less than 50% of the surface area of each sheet) of pressure-sensitive adhesive (like the repositionable sheets of the above-discussed Smith Pat. No. 4,416,392) or a wide band that covers one entire surface of each sheet (like the repositionable sheets described in the above-cited Miles et al U.S. Patent No. 4,907,825 and Blackwell U.S. Patent No. 5,086,946). Other sheets that may be useful to form stacks with the sheets in the stacks disposed as taught in the Smith Patent No. 4,416,392 are those sheets with both tab and body portions taught in U.S. Patent Application No. 08/084,798 filed June 29, 1993. Examples Sheet dispensers according to the present invention were made and were tested using the following tests for adhesion and release. Adhesion force measurement: This test measured the separation force of the coating of pressure-sensitive adhesive coating on the bottom layer of the dispenser from a standard glass surface. That coating of adhesive was applied to a clean surface on a glass plate. The dispenser was laminated to that glass surface using two passes of a 2 kg rubber roller over the entire dispenser sub assembly. The glass plate was attached to a stationary clamp of a constant-rate-extension device. The dispenser was peeled off the glass plate at 90 degrees at a speed of 30.5 cm/min in the direction parallel to the glass surface. The width of the coating of adhesive was measured in the direction perpendicular to the peel direction. The adhesion value was reported as the measured force per width of adhesive in units of grams per 2.54 cm. A plurality of examples of sheet dispensers according to the present invention were constructed from a durable card stock material, using stacks of paper sheets of the type described in U.S. Patent 4,781,306. Card stock 0.5 mm thick, was cut into sections 14.6 centimeters long x 6.3 cm wide, transverse slots, 3.2 cm x 1.2 cm were cut in the center. Strips of permanent double-coated tape, 1.2 cm wide, were secured along the narrow edges of the sections. The card stock was folded over the tape and laminated to form a permanent bond. The lowermost folded portions of the card stock had lengths of Scotch® Y-9415 tape laminated to them. The liner from the tape was removed to expose the repositionable adhesive. Stacks of 25 sheets were positioned along the inner surfaces of the cover layers with end portions of the uppermost sheets of the stacks projecting through the the slots. The dispensers had an adhesion to glass of about 140 g/2.54 centimeters, and had a thickness of about 3.32 mm. The stiff dispenser subassemblies were easy to find in a book, where the sheets from the dispensers were put to use. The present invention has now been described with reference to several embodiments thereof. It will be apparent to those skilled in the art that many changes can be made in the embodiments described without departing from the scope of the present invention. Thus the scope of the present invention should not be limited to the structures methods described in this application, but only by structures and methods described by the language of the claims and the equivalents of those structures and methods.

Claims: A pop-up sheet dispenser (20) comprising: (a) a stack (16) of sheets disposed one on top of another, each sheet comprising a backing having opposite first and second major side surfaces and opposite first and second ends with ends of the sheets being in alignment in the stack (16), and a layer (18) of adhesive permanently adhered to the first side surface of said backing, the layers (18) of adhesive of said sheets being releasably adhered along the second surfaces of the adjacent sheets in said stack (16), at least some of said sheets comprising release means for providing a first adhesion level along first end portions of said sheets adjacent said first ends of said backings between said first side surfaces and the second side surfaces of the adjacent sheets in the stack (16) to which the layers (18) of adhesive are releasably adhered, which first adhesion level provides a sufficiently low or no release force between said first side surfaces and the adjacent sheets to which the adhesive along those first side surfaces are releasable adhered to afford sliding movement between the side surfaces of the adjacent sheets along said first end portions, and attachment means for providing a second adhesion level along second end portions of said sheets adjacent said second ends of said backings between said layers (18) of adhesive and the second side surfaces of the adjacent sheets in the stack (16) to which said layers (18) of adhesive are releasably adhered, which second adhesion level provides a release force that is higher than said sufficiently low release force along said first end portions and firmly adhere the sheets to the adjacent sheets in the stack (16) during sliding movement of the sheets relative to the adjacent sheets along said first end portions while affording peeling away of the sheets from the stack (16) along said second end portions; (b) a cover layer (21) having inner and outer major surfaces, a central portion, a peripheral portion or portions on at least two opposite sides of said central portion, and a through slot (22) extending transversely across said central portion; (c) said stack (16) of sheets being positioned along the inner surface adjacent said central portion with the first end portion (27) of the uppermost sheet in the stack (16) extending through said slot (22); (d) a bottom layer (24) having inner and outer surfaces said bottom layer (24) extending over the inner surface of the cover layer (21) and the stack (16) of sheets and being attached to said peripheral portion of the cover layer (21) with the inner surface of the bottom layer (24) adjacent the cover layer (21) to form a chamber (25) around the stack (16) of sheets; (e) said stack (16) of sheets, slot (22) and chamber (25) being adapted to afford dispensing of the sheet having the first end portion (27) extending through the slot (22) when that first end portion (27) is manually pulled through the slot (22) by sequential sliding movement of one of the sheets relative to the adjacent sheet along the first end portion and peeling away of the sheet from the stack (16) along said second end portion, and positioning of the first end portion of an underlying sheet in a position extending through the slot (22) as a result of said dispensing; (f) said dispenser (20) further including a layer of pressure-sensitive adhesive (28) on the outer surface of the bottom layer (24); and a disposable release liner (29) over the surface of the layer (28) of pressure-sensitive adhesive layer opposite the bottom layer (24), which release liner (29) can be removed to permit the dispenser (20) to be adhered to a surface; said pop-up sheet dispenser (20) being characterized by the feature that (g) said cover layer (21) is supple and less than 0.2 millimeter (0.008 inch) in thickness; and (h) said bottom layer (24) is thin and supple. A pop-up sheet dispenser (20) according to claim 1 further characterized in that : (a) the first end of each sheet in the stack (16) is in alignment with the second end of an adjacent sheet in the stack (16), said sheets comprise release means for providing said first adhesion level along a first end portion of each of said sheets adjacent said first end of said backing between said first side surface and the second side surface of the adjacent sheet in the stack (16) to which the layer (18) of adhesive is releasably adhered, and attachment means for providing said second adhesion level along the second end portion of each of said sheets adjacent said second end of said backing between said layer (18) of adhesive and the second side surface of the adjacent sheet in the stack (16) to which said layer (18) of adhesive is releasably adhered; (b) said stack (16) of sheets includes a lowermost sheet that is free of adhesive; and (c) the slot (22), stack (16) of sheets, and chamber (25) are sized and positioned to afford shuttling back and forth motion of the stack (16) within the chamber (25) in a direction orthogonal to the transverse slot (12) when sheets of the stack (16) are successively pulled through said slot (22). A pop-up dispenser (20) according to claim 1 further characterized in that the bottom layer (24) is a polymeric film that is less than 0.13 mm in thickness. A pop-up dispenser (20) according to claim 1 further characterized in that each of the cover layer (11) and the bottom layer (24) has a thickness in the range of 0.02 to 0.05 millimeters. A pop-up dispenser (20) according to claim 1 further characterized in that the disposable release liner (29) is an elongate strip on which a plurality of identical pop-up dispensers (20) are positioned, said elongate strip of disposable release liner (29) and pop-up dispensers (20) being helically wound into a roll. A pop-up dispenser (20) according to claim 5 further characterized in that at least one of said cover and bottom layers (21, 24) of said plurality of pop-up dispensers (20) is provided by a substantially continuous polymeric film that is perforated between adjacent pop-up dispensers (20) to afford separation of the pop-up dispensers (20).

Inventors: DARVELL WAYNE K, MERTENS TIMOTHY A, MILES ALDEN R, WINDORSKI DAVID C, DARVELL, WAYNE K., MERTENS, TIMOTHY A., MILES, ALDEN R., WINDORSKI, DAVID C.
Applicants: MINNESOTA MINING & MFG, MINNESOTA MINING AND MANUFACTURING COMPANY
Application year: 1994
Main classification: B42D5
IPC codes: B42D5